Added CanvasPattern global flag for jshint

The core.helpers file was failing linting checks as the global CanvasPattern was not defined. Added the `/* global CanvasGradient */` statement to make linting pass. Updates chartjs/Chart.js#1323

diff --git a/src/core/core.helpers.js b/src/core/core.helpers.js
index 60673d8fa9cbd6f01a59716544aed24bb8b6389c..632883f8d30fe1bc4e40f9b218eb7ca746a0ce30 100644 (file)
--- a/src/core/core.helpers.js
+++ b/src/core/core.helpers.js
@@ -944,6 +944,7 @@ module.exports = function(Chart) {
                }
        };
        helpers.getHoverColor = function(color) {
+               /* global CanvasGradient */
                return (color instanceof CanvasPattern) ?
                        color :
                        helpers.color(color).saturate(0.5).darken(0.1).rgbString();